A filter for motor speed measurement signals includes one or more resonators configured to filter signals having a frequency that is proportional by a predetermined factor to the frequency of the motor whose speed is measured.

Apparatus and associated methods relate to a linear variable differential transformer (LVDT) probe. The LVDT probe includes a plunger rod and a metal sheet formed into a cylinder with a C-shaped cross-section, the metal sheet configured to couple to the plunger rod. In an illustrative example, the coupling may be an interference fit aided by spring retention forces of the metal sheet. The metal sheet may be stamped, formed and applied to the plunger rod without annealing. In another example, the C-shaped metal sheet may be welded to the plunger rod at a distal and/or proximal end. The ratio of relative electromagnetic permeability of the metal sheet to the plunger rod may be greater than 10.

A linear variable differential transducer (LVDT) includes a primary coil, a first secondary coil, and a second secondary coil. Each of the first and second secondary coils comprises a wound portion that is wound around a longitudinal axis of the LVDT, and first and second non-wound portions at either end of the wound portion. The wound portion meets the first and second non-wound portions at locations that are separated from each other in a direction along the longitudinal axis.

An example actuator assembly includes an actuator configured to move a rod. A variable differential transformer (VDT) is situated adjacent to the actuator. The VDT includes a core coupled to the rod such that movement of the rod causes a corresponding movement of the core. A plurality of windings surround the core for measuring displacement of the core. A shield surrounds the plurality of windings and shields the plurality of windings from a magnetic field of the actuator. The shield having a maximum permeability of 50,000-500,000. A LVDT configuration method is also disclosed.

An example actuator control system includes a variable differential transformer (VDT) configured to measure displacement of a motor, and a motor controller configured to control the motor based on displacement data from the VDT. A circuit card assembly (CCA) interconnects the VDT to the motor controller. The CCA includes memory storing configuration data of the VDT, and the CCA is configured to provide the configuration data to the motor controller to calibrate the motor controller for use of the VDT. A method of configuring a motor controller is also disclosed.

A plug gauge includes a housing, defining an internal volume, first openings, and second openings. The plug gauge includes first contact elements, each at least partially received in a respective one of the first openings. The plug gauge includes a first plunger in the internal volume and movable relative to the housing. The first plunger is biased to urge the first contact elements radially outward through the first openings. The plug gauge includes a first sensor sensing movement of the first plunger. The plug gauge includes second contact elements, each at least partially received in a respective one of the second openings. The plug gauge includes a second plunger in the internal volume and movable relative to the housing. The second plunger is biased to urge the second contact elements radially outward through the second openings. The plug gauge includes a second sensor sensing movement of the second plunger.

Multiple deflections of a structural member (SM) can be measured at multiple locations thereof, which deflections can be used to monitor changes in stiffness over time, using at least one antenna to measure the resonant frequencies at different harmonic frequency numbers of a predetermined radio frequency spectrum. One antenna can include a plurality of coils providing a first coil region that has a maximum sensitive to a first resonant frequency harmonic number and another antenna can include a plurality of coils providing a second coil region that has a maximum sensitivity to a second resonant frequency harmonic number that is different from the first predetermined resonant frequency harmonic number. Using different harmonic resonant frequency numbers, deflections at multiple regions of the SM can be determined concurrently using a plurality of antennae.

A method of measuring a movement, the method comprising the steps of: acquiring and digitizing both a first measurement voltage across the terminals of a first secondary winding and also a second measurement voltage across the terminals of a second secondary winding of an inductive movement sensor; multiplying the first measurement voltage by itself in order to obtain a first component of a crossed vector, multiplying the second measurement voltage by itself in order to obtain a second component of the crossed vector, and multiplying together the first measurement voltage and the second measurement voltage in order to obtain a third component of the crossed vector; applying the crossed vector as input to a lowpass filter in order to obtain a filtered vector, and estimating the movement from the components of the filtered vector.

An electromagnetic device is disclosed, the electromagnetic device comprising a core support having an exterior surface comprising at least one radial protrusion, a tubular magnetic core positioned around a portion of the length of the core support, the tubular magnetic core having an interior surface, at least one indent located in the interior surface of the tubular magnetic core, wherein the at least one protrusion is located within the at least one indent to prevent relative longitudinal movement between the core support and tubular magnetic core, and a primary coil and at least one secondary coil, each coil positioned around a portion of a length of the tubular magnetic core.

A turbine speed probe diagnostic system is provided. The turbine includes a speed probe and a speed reading circuit. A speed lead connects the speed probe and speed reading circuit together to transmit speed signals from the speed probe to the speed reading circuit. A speed probe diagnostic circuit is also provided for connection to the speed lead. An isolation switch is provided to isolate the speed probe diagnostic circuit during normal operation when the speed reading circuit is receiving speed signals from the speed probe. When no speed signals are being received, the isolation switch closes and the speed probe diagnostic circuit performs a test on the speed probe or speed lead.